body {
  background-color: #ddd;
}
.box {
  width: 375px;
  margin: 0 auto;
  background-color: #fff;
  padding: 10px;
  font-size: 14px;
}
.box .nav {
  display: flex;
  align-items: center;
}
.box .nav div {
  background-color: #ddd;
  border-radius: 5px;
  padding: 2px 5px;
  margin-right: 5px;
  cursor: pointer;
}
.box .nav div.active {
  background-color: #2c4cdb;
  color: #fff;
}
.box ul {
  display: none;
  padding: 10px 0;
}
.box ul li {
  color: #2c4cdb;
  line-height: 21px;
}
.box ul.active {
  display: block;
}
